1. Field of the Invention
The present invention relates to neghold assemblies for positioning and aligning selected film frames of a disc-like film unit at the print gate of a photographic printer.
2. Description of the Prior Art
Apparatus for holding and indexing conventional strip film on a photographic printer so that selected image frames are positioned at a print gate for transfer of the image to photographic print paper are well known in the art. However, this type of apparatus is wholly unsuited for positioning selected image frames of a disc-like film unit at a print gate wherein the individual image frames are located circumferentially about a central hub. Examples of a disc film unit are disclosed in the following U.S. patents:
______________________________________ Inventor U.S. Pat. No. ______________________________________ Sethi 4,194,822 Morse 4,208,116 Harvey et al 4,208,117 Sethi et al 4,212,673 Harvey et al 4,255,034 Harvey 4,264,169 Harvey et al 4,268,145 ______________________________________
A print gate indexing device for a disc-like film unit is disclosed in Research Disclosure of August, 1978, Disclosure No. 17287. Using the print gate indexing device, each image frame is manually advanced into the print gate. The disc-like film unit is held in a single horizontal plane while selected image frames are rotationally indexed to the print gate. However, the mechanism illustrated in Disclosure No. 17287 is unsuitable for semi-automatic or automatic photographic printers.
A rotational positioning device is also disclosed in Research Disclosure of August, 1978, Disclosure No. 17289. The rotational positioning device includes an assembly from which a central shaft extends upwardly for coaxially centering the disc-like film unit on the assembly. A pair of pins also extend upward from the assembly for extending through cooperting apertures in the hub of the disc film unit. No suitable mechanism is shown for placing the rotational positioning device in a print exposure cycle position at the print gate of a photographic printer.
The Clifton et al U.S. Pat. No. 4,203,664 and the Modney et al U.S. Pat. No. 4,202,733 illustrate a film positioning apparatus for supporting and positioning a disc-shaped film unit having a plurality of images, in several spaced work positions on a photographic printer, including one position where the film unit is supported adjacent the printing gate aperture. The apparatus disclosed in the Clifton et al and the Modney et al patents is, however, unnecessarily complicated for positioning a disc film unit adjacent the print gate aperture.